The present invention discloses a set of genes which have been demonstrated to be anomalously regulated (i.e., dysregulated) in a model of combining a pathophysiological predisposition towards stroke, hypertension, diabetes and obesity. The present invention also relates to methods of treating and/or preventing stroke, hypertension, diabetes or obesity by the administration of the nucleic acids or protein products (and derivative and analogs thereof) of the GENE SET which are defective and/or are of low abundance in humans. The present invention further relates to methodologies of diagnosis, prognosis and screening for alleles of the GENE SET which may cause or predispose to the aforementioned diseases.
Prevalent human diseases such as hypertension, non-insulin dependent diabetes (NIDDM), stroke, and obesity (dyslipidemia) have been shown to possess a significant genetic component composed of multiple, perhaps numerous, underlying genetic defects. Human Metabolic Syndrome X, a relatively common but poorly understood disorder, has been shown to possess a significant genetic component which is comprise of an association of the pathophysiologies of hypertension, insulin resistance, dyslipidemia and abdominal obesity. See e.g., Ferrannini, et al., 1987. New Engl. J. Med. 317:350-357; Kaplan, 1989. Arteriosclerosis 9:335-344. Given the prevalence of this combination of diseases, many research groups have focussed their efforts upon determining the etiology (i.e., the primary causative genetic defects) of Metabolic Syndrome X in humans and closely-associated animal models.
The most successfully studied of these aforementioned diseases to date is hypertension, with strong evidence nucleotide sequence variants, with their associated amino acid residue substitutions, within a total of 11 human genes affect blood pressure. See e.g., Shimkets, et al., 1994. Cell 79(3):407-414; Simon, et al., 1997. Nat. Genet. 17(2):171-178; Geller, et al., 1998. Nat. Genet. 19(3):279-281. While in all probability these variants, in toto, account for only a fraction of the variation in blood pressure within the general population, they, nonetheless, serve to illustrate the potential that the etiology of many such diseases may involve the interaction of a large number of genetic components. As the majority of the genetic components of complex diseases such as human Metabolic Syndrome X have yet to be elucidated, a comprehensive analysis for the genetic defects responsible for the phenotype was undertaken in the present invention within a closely-associated animal model of this syndrome.
The most widely-utilized and generally-accepted model of human Metabolic Syndrome X is the spontaneously hypertensive rat (SHR), which is characterized by the pathophysiologies of salt-induced hypertension, insulin resistance and increased abdominal fat. See e.g., Yamori, 1984. Experimental and Genetic Models of Hypertension In: Handbook of Hypertension (Elsevier Science Publishers, New York, N.Y.). While many genetic loci have been linked to various aspects of the SHR phenotype relative to those of the Wistar Kyoto (WKY) control strain, only a single gene defect has been implicated as a causative factor in the phenotype. See e.g., Aitman, et al., 1997. Nat. Genet. 16(2):197-201; Clark, et al., 1996. Hypertension 28(5):898-906; Bottger, et al., 1996. J. Clin. Invest. 98(3):856-862. In addition, a spontaneous variant of the SHR was found which, in addition to the features of human Metabolic Syndrome X, undergoes severe hemmhoragic or ischemic stroke. This strain was designated SHR stroke-prone (SHR-SP). See e.g., Okamoto, et al., 1974. Circ. Res. 33/34:I-143-153; Rabattu, et al., 1996. Nat. Genet. 16(4):364-367. Prior to the present invention, the gene(s) influencing the manifestation and latency period of stroke within SHR-SP animals have also not been identified.
In order to identify the primary genetic defects leading to the phenotype of the SHR and SHR-SP, the present invention has included a comprehensive gene expression analysis utilizing the GeneCalling(copyright) technology to identity the majority of differentially-expressed genes between the strains of animals that were used for genetic linkage analysis. GeneCalling(copyright) not only identifies both known and novel differentially-expressed genes, but also identifies sequence variations in complementary DNA (cDNA) between the various strains being compared. These variations detected by GeneCalling(copyright) can include, but are not limited to, insertions, deletions and single base-pair changes.
In order to identify, in the most efficacious manner possible, which of the differentially-expressed genes may contribute directly to the phenotype, the genes were placed on the physical map of the rat using a radiation hybrid panel. Given the statistical improbability of each xe2x80x9ceventxe2x80x9d occurring by chance, genes which were found to be both differentially-expressed within the different animal strains and tissues/organs and to map within quantitative trait loci (QTL), were deemed to have a high probability of possessing mutations which would affect the phenotype.
Presented herein is the first comprehensive organ survey of differences in gene expression in a genetic disease model coupled with a comprehensive mapping and mutation detection strategy to identify the gene(s) responsible for causing or predisposing to these aforementioned disease traits.
It should be noted that the citation or discussion of a reference herein shall not be construed as an admission that such is prior art to the present invention.
The present invention discloses the use of genes within a GENE SET, or mutations of the genes within the GENE SET, as diagnostics and therapeutics for disease.
More specifically, the present invention discloses nucleic acid sequences comprising the genes of a GENE SET, the proteins encoded therefrom and derivatives, analogs and mutations thereof, for use in the diagnosis, prognosis and screening, as well as the treatment, both prophylactic and therapeutic, of diseases such as hypertension, diabetes (insulin resistance), obesity/dyslipidemia and stroke (ischemic disease).
Further disclosed herein are methodologies of diagnosis, prognosis, and screening by detecting genes from the GENE SET. Diagnostic, prognostic and screening kits are also provided.
Additionally, the present invention also discloses methods of screening for modulators of GENE SET activity which affect hypertension, diabetes, obesity and both the latency period and severity of stroke.